Right now we rely on rockets to launch things like satellites and supplies for the International Space Station into space.

But just one rocket costs over $60 million, and you can only use it once. Amazon founder and space entrepreneur Jeff Bezos has compared it to using a 747 to fly across the country once and then throwing the plane away.

Instead of throwing away $60 million on every single launch, reuseable rockets could fly over and over again. The only cost per launch would be a few replacement parts and about $200,000 for rocket fuel.

A reusable rocket is no easy feat though. SpaceX released a graphic that shows a step by step schematic of how their revolutionary rocket technology works:

First, the giant 229-foot-tall rocket launches:

SpaceX/Flickr

Then the rocket separates into two parts. The top part called stage 2 continues upward and carries the payload into space. The bottom part called stage 1 is the piece that SpaceX will try to land back on Earth.

SpaceX/Flickr

You can see the second stage continues on into space, but thrusters on the first stage fire to flip that piece of the rocket around and point it back towards Earth.

SpaceX/Flickr

Some of the engines on the first stage briefly reignite to get the rocket lined up for a landing. Small grid fins open on the sides to help steer the rocket during the landing.

SpaceX/Flickr

Once the rocket gets close to Earth, the engines light again to help it slow down before the landing. The grid fins help keep the rocket oriented in the right direction.

SpaceX/Flickr

A sophisticated navigation system tells the rocket where to land. When all goes according to plan, it looks something like this:

Previously, SpaceX attempted to land its rocket on a barge at sea. Those tries have all been unsuccessful:

But this time SpaceX switched things up. It landed the rocket on dry land at Cape Canaveral's new Landing Zone 1 — a much more steady target than a ship being tossed in the waves.

Jeff Bezos' rocket company Blue Origin already successfully landed a rocket back in November, but what SpaceX is attempting is different, and much, much harder.

Blue Origin is only interested in space tourism, which involves launching spacecraft to the edge of space (roughly 62 miles above Earth) where paying passengers can experience zero gravity for a few minutes.

So Blue Origin's rocket isn't nearly powerful enough to put a spacecraft or satellites into orbit — that requires about 100 times more energy.

SpaceX's rocket, on the other hand, actually launched a satellite into space before the landing tonight. That means the rocket traveled higher and faster — making the landing much more difficult to pull off than Blue Origin's.